Pentraxin 3 (PTX3) and C-reactive protein (CRP) are members of the pentraxin superfamily. PTX3 expression is induced in response to inflammatory signals, and is produced at sites of inflammation by several types of cell, primarily monocytes/macrophages, dendritic cells (DCs), endothelial cells, smooth muscle cells (SMCs), and fibroblasts, but is not produced by hepatocytes, which are a major source of CRP. The aim of our study was to investigate the expression pattern of PTX3 in human atherosclerotic lesions using a novel monoclonal antibody against PTX3. We examined coronary arterial thrombi containing an atherosclerotic plaque component removed from patients with acute myocardial infarction and human aortic tissues with various degrees of atherosclerosis sampled from autopsy cases. Immunohistochemical study of paraffin and frozen sections indicated that macrophages, mainly foam cells, expressed PTX3 in advanced atherosclerotic lesions. Interestingly, we also clearly observed PTX3-positive neutrophils infiltrating into atherosclerotic plaques, suggesting that PTX3 derived from neutrophils as well as macrophages plays an important role in atherogenesis.

Abstract

We report three patients with tubulointerstitial nephritis (TIN) with high serum IgG4 concentrations. None of the patients had notable pancreatic lesions when the TIN developed, although one had a history of autoimmune pancreatitis (AIP). Nevertheless, the clinicopathological findings were quite similar to those of AIP. They were all middle-aged to elderly men. Sialadenitis and lymphadenopathy were often evident. Serum total IgG and IgG4 concentrations were elevated and hypocomplementemia was observed. Although antinuclear antibodies were positive, anti-Ro and anti-La antibodies were negative. Renal biopsy showed dense lymphoplasmacytic infiltration with fibrosis in the renal interstitium, and the infiltrated plasma cells had strong immunoreactivity for IgG4. Furthermore, lymphoplasmacytic infiltration and abundant IgG4-positive plasma cells were observed in the salivary glands of a patient. Steroid therapy was effective for TIN in all three patients. The present findings support the recently proposed concept of IgG4-related systemic disease, and suggest that IgG4 is associated not only with AIP but also with other systemic lymphoplasmacytic diseases, including TIN. The conditions responsible for the pathogenesis of TIN need to be considered, irrespective of the presence of AIP.

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